Prepare me a table including the muscles of upper limb, their origin and insertion and main points to remember if any
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I now have all the data I need. Let me compile the comprehensive table from the textbooks.
Here is a comprehensive reference table of the muscles of the upper limb, organized by region, with origin, insertion, action, innervation, and key clinical/exam points. Sources: Miller's Review of Orthopaedics 9th Ed, Gray's Anatomy for Students, THIEME Atlas of General Anatomy, and Imaging Anatomy Volume 3.
Muscles of the Upper Limb
1. Shoulder Girdle Muscles
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Trapezius | Spinous processes C7-T12, external occipital protuberance, ligamentum nuchae | Clavicle (lateral third), acromion, scapular spine | Upper: elevates scapula; Middle: retracts scapula; Lower: depresses scapula; all parts rotate glenoid upward | Cranial nerve XI (spinal accessory) + C3, C4 | Only muscle innervated by a cranial nerve in the limb. Palsy causes shoulder drop and inability to raise arm above 90° |
| Serratus anterior | Outer surfaces of ribs 1-9 | Costal (ventral) surface of medial border of scapula | Protracts and rotates scapula (tilts glenoid upward); holds scapula against chest wall | Long thoracic nerve (C5, C6, C7) | Palsy causes "winging of scapula." Long thoracic nerve runs on the surface of the muscle - easily injured |
| Pectoralis major | Clavicle (medial half), sternum, costal cartilages 1-6 | Lateral lip of intertubercular (bicipital) groove of humerus | Adduction, medial rotation, flexion (clavicular head) of arm | Medial and lateral pectoral nerves (C5-T1) | Clavicular head flexes; sternocostal head extends. Rupture common in weightlifters during bench press |
| Pectoralis minor | Ribs 3-5 (anterior surface) | Coracoid process of scapula | Protracts and depresses scapula; assists forced inspiration | Medial pectoral nerve (C8, T1) | Used as a landmark - the brachial plexus cords are named by their relationship to pectoralis minor |
| Subclavius | Rib 1 (junction of rib and costal cartilage) | Inferior surface of middle third of clavicle | Depresses and steadies clavicle | Nerve to subclavius (C5, C6) | Protects subclavian vessels in clavicle fracture |
| Levator scapulae | Transverse processes of C1-C4 | Superior angle of scapula (medial border) | Elevates scapula; rotates glenoid downward | Dorsal scapular nerve (C3, C4, C5) | Part of the floor of the posterior triangle of the neck |
| Rhomboid major | Spinous processes T2-T5 | Medial border of scapula (below spine) | Retracts and elevates scapula; rotates glenoid downward | Dorsal scapular nerve (C4, C5) | Both rhomboids tested together by asking patient to brace shoulders back |
| Rhomboid minor | Spinous processes C7-T1, lower ligamentum nuchae | Medial border of scapula (at level of spine) | Retracts scapula; rotates glenoid downward | Dorsal scapular nerve (C4, C5) | Lies above rhomboid major |
2. Rotator Cuff & Posterior Shoulder Muscles
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Supraspinatus | Supraspinous fossa of scapula | Superior facet of greater tubercle of humerus | Initiates abduction (0-15°); stabilizes humeral head | Suprascapular nerve (C5, C6) | Most commonly torn rotator cuff muscle. Critical zone of relative avascularity 1 cm from insertion. "Empty can" test |
| Infraspinatus | Infraspinous fossa of scapula | Middle facet of greater tubercle of humerus | Lateral (external) rotation of arm | Suprascapular nerve (C5, C6) | 2nd most commonly torn. Tests: external rotation against resistance, "hornblower's sign" if torn |
| Teres minor | Upper 2/3 of lateral border of scapula | Inferior facet of greater tubercle of humerus | Lateral (external) rotation; adduction of arm | Axillary nerve (C5, C6) | Part of rotator cuff (SITS). Rarely torn in isolation |
| Subscapularis | Subscapular fossa (anterior surface of scapula) | Lesser tubercle of humerus | Medial (internal) rotation; adduction; stabilizes glenohumeral joint | Upper and lower subscapular nerves (C5, C6) | Largest and strongest rotator cuff muscle. Tests: "Lift-off test," "Bear-hug test," Napoleons sign |
| Deltoid | Clavicular part: lateral 1/3 of clavicle; Acromial part: acromion; Spinal part: scapular spine | Deltoid tuberosity of humerus | Clavicular: flexion, medial rotation; Acromial: abduction (main); Spinal: extension, lateral rotation | Axillary nerve (C5, C6) | Most powerful abductor above 15°. All three parts act together during abduction >60°. Axillary nerve vulnerable in anterior shoulder dislocation and surgical neck fracture |
| Teres major | Inferior angle and posterior surface of lateral border of scapula | Medial lip of intertubercular groove of humerus | Adduction, medial rotation, extension of arm | Lower subscapular nerve (C6, C7) | "Little lat" - same action as latissimus dorsi. NOT part of rotator cuff |
| Latissimus dorsi | Spinous processes T6-S5, thoracolumbar fascia, iliac crest, lower 3-4 ribs | Floor of intertubercular groove of humerus | Extension, adduction, medial rotation of arm | Thoracodorsal nerve (C6, C7, C8) | Used in breast reconstruction (latissimus dorsi flap). Tested by asking patient to cough while placing hand on the muscle |
| Coracobrachialis | Apex of coracoid process of scapula | Linear roughening on midshaft of humerus (medial side) | Flexion and adduction of arm at glenohumeral joint | Musculocutaneous nerve (C5, C6, C7) | Musculocutaneous nerve pierces this muscle. Landmark for axillary artery |
3. Muscles of the Arm (Brachium)
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Biceps brachii | Short head: apex of coracoid process; Long head: supraglenoid tubercle of scapula (tendon passes through glenohumeral joint within intertubercular sulcus) | Radial tuberosity; bicipital aponeurosis (lacertus fibrosus) into deep fascia of forearm | Powerful flexion of forearm at elbow; supination (most powerful when elbow at 90°); weak flexion of shoulder | Musculocutaneous nerve (C5, C6) | Long head tendon held in groove by transverse humeral ligament. LHBT rupture causes "Popeye sign." Biceps curl activates both heads. "Speed's test" for LHBT pathology |
| Brachialis | Anterior surface of lower half of humerus (medial and lateral) | Tuberosity (coronoid process) of ulna | Powerful flexion of forearm at elbow joint (in all positions) | Musculocutaneous nerve (C5, C6); small radial nerve contribution (C7) to lateral part | Only true pure flexor of the elbow. Works in both pronation and supination. Injury can lead to myositis ossificans |
| Triceps brachii | Long head: infraglenoid tubercle of scapula; Lateral head: posterior humerus above radial groove; Medial head: posterior humerus below radial groove | Olecranon process of ulna | Extension of forearm; long head also extends and adducts shoulder | Radial nerve (C6, C7, C8) | Radial nerve runs in spiral groove between lateral and medial heads. Humeral midshaft fracture = radial nerve palsy = wrist drop. Only extensor of the forearm |
| Anconeus | Lateral epicondyle of humerus | Lateral aspect of olecranon and posterior ulna | Assists triceps in extension; abducts ulna in pronation | Radial nerve (C7, C8) | Continuous with medial head of triceps. Minor extensor |
4. Forearm Muscles - Anterior (Flexor) Compartment
Superficial Layer
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Pronator teres | Medial epicondyle (humeral head) + coronoid process (ulnar head) | Middle of lateral surface of radius | Pronation of forearm; assists elbow flexion | Median nerve (C6, C7) | Median nerve passes between two heads - can be compressed here (pronator syndrome). Tightened in "palm down" position |
| Flexor carpi radialis (FCR) | Medial epicondyle (common flexor origin) | Bases of 2nd and 3rd metacarpals | Wrist flexion; radial deviation | Median nerve (C6, C7) | Tendon is a landmark for radial artery (artery lies lateral to it). Passes through its own tunnel in the flexor retinaculum |
| Palmaris longus | Medial epicondyle | Palmar aponeurosis and flexor retinaculum | Tenses palmar aponeurosis; wrist flexion | Median nerve (C7, C8) | Absent in ~14% of population. Used as tendon graft donor. Visible on surface when wrist is flexed with thumb and little finger apposed |
| Flexor carpi ulnaris (FCU) | Medial epicondyle (humeral head) + posterior ulna (ulnar head) | Pisiform, hook of hamate, base of 5th metacarpal | Wrist flexion; ulnar deviation | Ulnar nerve (C7, C8) | Only forearm flexor innervated by ulnar nerve. Ulnar nerve runs medial to FCU tendon at wrist (Guyon's canal) |
| Flexor digitorum superficialis (FDS) | Medial epicondyle, coronoid process, anterior oblique line of radius | Sides of middle phalanges (2-5) via split tendon | Flexion of PIP joints; assists wrist and MCP flexion | Median nerve (C7, C8, T1) | Tendon splits (Camper's chiasm) to allow FDP to pass through. FDS to middle and ring fingers are most volar in carpal tunnel. Test by flexing individual PIP while holding other fingers extended |
Deep Layer
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Flexor digitorum profundus (FDP) | Anterior and medial surfaces of proximal 3/4 of ulna, interosseous membrane | Bases of distal phalanges (2-5) | Flexion of DIP joints; assists PIP, MCP, wrist flexion | Medial half (ring, little): Ulnar nerve (C8, T1); Lateral half (index, middle): Anterior interosseous nerve - branch of median (C8, T1) | Profundus passes through Camper's chiasm of FDS. Jersey finger = avulsion of FDP from distal phalanx. Medial two digits = ulnar; Lateral two = AIN (median) |
| Flexor pollicis longus (FPL) | Anterior surface of radius, interosseous membrane | Base of distal phalanx of thumb | Flexion of IP joint of thumb | Anterior interosseous nerve (branch of median, C8, T1) | Only long flexor of the thumb. AIN palsy: loss of FPL + FDP to index + pronator quadratus ("OK sign" failure) |
| Pronator quadratus | Distal quarter of anterior ulna | Distal quarter of anterior radius | Pronation of forearm | Anterior interosseous nerve (C8, T1) | Deepest muscle; primary pronator in slow deliberate pronation. Important in distal radius fracture repair |
5. Forearm Muscles - Posterior (Extensor) Compartment
Superficial Layer
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Brachioradialis | Lateral supracondylar ridge of humerus | Lateral surface of distal radius (styloid process) | Flexion of forearm at elbow (especially from mid-pronation/supination) | Radial nerve (C5, C6) | Only muscle of posterior compartment that flexes (not extends). Forms lateral border of cubital fossa. Part of "mobile wad" |
| Extensor carpi radialis longus (ECRL) | Lateral supracondylar ridge of humerus | Base of 2nd metacarpal (dorsal) | Wrist extension; radial deviation | Radial nerve (C6, C7) | Runs in 2nd extensor compartment with ECRB. "Mobile wad" muscle |
| Extensor carpi radialis brevis (ECRB) | Lateral epicondyle (common extensor origin) | Base of 3rd metacarpal (dorsal) | Wrist extension; slight radial deviation | Radial nerve / Posterior interosseous nerve (C7, C8) | Most commonly involved tendon in lateral epicondylitis ("tennis elbow"). Runs in 2nd extensor compartment |
| Extensor digitorum (ED) | Lateral epicondyle (common extensor origin) | Extensor expansion / dorsal digital expansion of fingers 2-5 | Extension of MCP and IP joints of fingers 2-5; assists wrist extension | Posterior interosseous nerve (C7, C8) | Interconnected at dorsum by juncturae tendinum. Cannot fully extend individual fingers independently |
| Extensor digiti minimi (EDM) | Common extensor tendon (lateral epicondyle) | Extensor expansion of little finger (5th) | Extension of little finger MCP and IP joints | Posterior interosseous nerve (C7, C8) | Runs in 5th extensor compartment |
| Extensor carpi ulnaris (ECU) | Lateral epicondyle + posterior border of ulna | Base of 5th metacarpal (dorsal) | Wrist extension; ulnar deviation | Posterior interosseous nerve (C7, C8) | Runs in 6th extensor compartment. ECU tendinopathy is common cause of ulnar-sided wrist pain |
| Anconeus | Lateral epicondyle | Olecranon, posterior ulna | Extends elbow; tenses elbow capsule | Radial nerve (C7, C8) | (Also listed under arm muscles - functions at elbow) |
Deep Layer
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Supinator | Lateral epicondyle, radial collateral ligament, annular ligament, supinator crest of ulna | Lateral surface of proximal radius | Supination of forearm | Posterior interosseous nerve (C6, C7) | Radial nerve (PIN) passes through Arcade of Frohse (fibrous arch of supinator) - compression causes "radial tunnel syndrome" / PIN palsy |
| Abductor pollicis longus (APL) | Posterior surface of ulna and radius, interosseous membrane | Base of 1st metacarpal (radial side) | Abduction and extension of thumb at CMC joint; radial deviation of wrist | Posterior interosseous nerve (C7, C8) | Runs in 1st extensor compartment with EPB. Both involved in de Quervain's tenosynovitis |
| Extensor pollicis brevis (EPB) | Posterior surface of radius, interosseous membrane | Base of proximal phalanx of thumb | Extension of MCP joint of thumb | Posterior interosseous nerve (C7, C8) | Runs in 1st extensor compartment with APL. De Quervain's tenosynovitis affects APL + EPB |
| Extensor pollicis longus (EPL) | Posterior surface of ulna (middle third), interosseous membrane | Base of distal phalanx of thumb | Extension of IP joint of thumb; extends and adducts thumb at CMC | Posterior interosseous nerve (C7, C8) | Wraps around Lister's tubercle (3rd extensor compartment). Spontaneous rupture occurs in undisplaced distal radius fractures (due to vascular compromise at Lister's tubercle) |
| Extensor indicis (EI) | Posterior surface of ulna, interosseous membrane | Extensor expansion of index finger | Extension of index finger (independently) | Posterior interosseous nerve (C7, C8) | Allows independent extension of index finger. Useful for tendon transfer |
6. Six Extensor Compartments of the Wrist (Mnemonic: 2-2-1-2-1-1)
| Compartment | Tendons |
|---|---|
| 1st | APL, EPB (de Quervain's) |
| 2nd | ECRL, ECRB |
| 3rd | EPL (wraps around Lister's tubercle) |
| 4th | ED, EI |
| 5th | EDM |
| 6th | ECU |
7. Hand Intrinsic Muscles
Thenar Muscles
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Abductor pollicis brevis (APB) | Scaphoid tubercle, trapezium, flexor retinaculum | Base of proximal phalanx of thumb (radial side) | Abduction of thumb (perpendicular to palm) | Median nerve (C8, T1) | First muscle to be affected in carpal tunnel syndrome (thenar wasting) |
| Opponens pollicis | Trapezium, flexor retinaculum | Entire length of 1st metacarpal (radial side) | Opposition of thumb (combination of abduction, flexion, medial rotation) | Median nerve (C8, T1) | Deepest thenar muscle. Opposition is the most important movement of the thumb |
| Flexor pollicis brevis (FPB) | Trapezium, capitate, flexor retinaculum | Base of proximal phalanx of thumb (radial side) | Flexion of MCP joint of thumb | Superficial head: Median nerve; Deep head: Ulnar nerve (C8, T1) | Dual innervation - only muscle with both median and ulnar supply |
| Adductor pollicis | Oblique head: capitate, bases of 2nd and 3rd metacarpals; Transverse head: shaft of 3rd metacarpal | Base of proximal phalanx of thumb (ulnar side) via sesamoid | Adduction of thumb | Ulnar nerve (C8, T1) | NOT in thenar eminence (lies deeper). Froment's sign: when asked to grip paper between thumb and index, flexes thumb IP due to FPL compensation for adductor pollicis weakness |
Hypothenar Muscles
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Palmaris brevis | Transverse carpal ligament, palmar aponeurosis | Ulnar skin of palm | Corrugates ulnar palm; deepens hypothenar hollow | Superficial branch of ulnar nerve (C8, T1) | Only intrinsic hand muscle not deep to palmar fascia. Protects ulnar nerve at Guyon's canal |
| Abductor digiti minimi (ADM) | Pisiform | Base of proximal phalanx of little finger (ulnar side) | Abduction of little finger | Deep branch of ulnar nerve (C8, T1) | Most laterally placed hypothenar muscle |
| Flexor digiti minimi brevis (FDMB) | Hook of hamate, flexor retinaculum | Base of proximal phalanx of little finger (ulnar side) | Flexion of MCP joint of little finger | Deep branch of ulnar nerve (C8, T1) | |
| Opponens digiti minimi (ODM) | Hook of hamate, flexor retinaculum | Medial border of 5th metacarpal | Opposition of little finger | Deep branch of ulnar nerve (C8, T1) | Mirror image of opponens pollicis |
Other Intrinsic Muscles
| Muscle | Origin | Insertion | Action | Innervation | Key Points |
|---|---|---|---|---|---|
| Lumbricals (4) | Tendons of FDP (1st and 2nd: radial side of each tendon unipennate; 3rd and 4th: bipennate from adjacent tendons) | Lateral bands of extensor expansion (radial side) of fingers 2-5 | Flex MCP joints; extend PIP and DIP joints | 1st and 2nd: Median nerve; 3rd and 4th: Ulnar nerve (C8, T1) | Only muscles with no bony origin or insertion. Paradox: they originate from tendons that cross the wrist and insert into extensors. Lumbricals + interossei = intrinsic plus position |
| Dorsal interossei (4) | Adjacent sides of 2 metacarpals (bipennate) | Bases of proximal phalanges and extensor expansion | ABduction of fingers (DAB); flex MCP; extend PIP/DIP | Ulnar nerve (C8, T1) | Reference axis = middle (3rd) finger. 1st DI: index ABduction (tested to assess ulnar nerve) |
| Palmar interossei (3) | Single metacarpal (unipennate - palmar surface) | Base of proximal phalanx and extensor expansion | ADduction of fingers (PAD); flex MCP; extend PIP/DIP | Ulnar nerve (C8, T1) | PAD = Palmar ADduct; DAB = Dorsal ABduct |
Key Clinical Points Summary
| Topic | Detail |
|---|---|
| Rotator cuff (SITS) | Supraspinatus, Infraspinatus, Teres minor, Subscapularis - all stabilize the humeral head in the glenoid |
| Wrist drop | Radial nerve injury in radial groove (midshaft humerus fracture) - loss of all wrist and finger extensors |
| Claw hand | Ulnar nerve injury - "intrinsic minus" - hyperextension of MCP, flexion of PIP/DIP in ring and little fingers. Distal injury = worse claw (Ulnar paradox) |
| Ape/Simian hand | Median nerve injury (combined CTS or high lesion) - thenar wasting, loss of opposition, thumb lies in same plane as palm |
| Winging of scapula | Long thoracic nerve palsy → serratus anterior weakness |
| Anterior interosseous nerve (AIN) palsy | Loss of FDP (index, middle), FPL, pronator quadratus → cannot make "OK sign" |
| Froment's sign | Adductor pollicis weakness (ulnar nerve) - compensated by FPL (median nerve) |
| Carpal tunnel contents | 9 tendons (4 FDS, 4 FDP, 1 FPL) + median nerve. A2 and A4 pulleys are most important |
| Mnemonic: SITS | Rotator cuff; all insert on greater tubercle except Subscapularis (lesser tubercle) |
| Mnemonic: PAD DAB | Palmar interossei ADduct; Dorsal interossei ABduct |
Sources: Miller's Review of Orthopaedics 9th Ed (2026); Gray's Anatomy for Students; THIEME Atlas of General Anatomy & Musculoskeletal System; Imaging Anatomy Vol. 3
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